Resizing UITextView

There is an answer posted at How do I size a UITextView to its content?

CGRect frame = _textView.frame;
frame.size.height = _textView.contentSize.height;
_textView.frame = frame;

or better(taking into account contentInset thanks to kpower's comment)

CGRect frame = _textView.frame;
UIEdgeInsets inset = textView.contentInset;
frame.size.height = _textView.contentSize.height + inset.top + inset.bottom;
_textView.frame = frame;

note: If you are going to reference a property of an object many times(e.g. frame or contentInset) it's better to assign it to a local variable so you don't trigger extra method calls(_textView.frame/[_textView frame] are method calls). If you are calling this code a lot(100000s of times) then this will be noticeably slower(a dozen or so method calls is insignificant).

However... if you want to do this in one line without extra variables it would be

_textView.frame = CGRectMake(_textView.frame.origin.x, _textView.frame.origin.y, _textView.frame.size.width, _textView.contentSize.height + _textView.contentInset.top + _textView.contentInset.bottom);

at the expense of 5 extra method calls.

sizeToFit Does Work

If you call sizeToFit after you set the text the first time it resizes. So after the first time you set it subsequent calls to set text will result in no change in size. Even if you call sizeToFit.

However, you can force it to resize like this:

1. Set the text.
2. Change the textView frame height to be CGFLOAT_MAX.
3. Call sizeToFit.

textView.contentSize.height in the textViewDidChange can only resize after text actually grows. For best visual result better to resize beforehand. After several hours I've figured out how to make it the same perfectly as in Instagram (it has the best algorithm among all BTW)

Initialize with this:

    // Input
    _inputBackgroundView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0f, size.height - _InputBarHeight, size.width, _InputBarHeight)];
    _inputBackgroundView.autoresizingMask = UIViewAutoresizingNone;
   _inputBackgroundView.contentMode = UIViewContentModeScaleToFill;
    _inputBackgroundView.userInteractionEnabled = YES;
    [self addSubview:_inputBackgroundView];
   [_inputBackgroundView release];

   [_inputBackgroundView setImage:[[UIImage imageNamed:@"Footer_BG.png"] stretchableImageWithLeftCapWidth:80 topCapHeight:25]];

    // Text field
    _textField = [[UITextView alloc] initWithFrame:CGRectMake(70.0f, 0, 185, 0)];
   _textField.backgroundColor = [UIColor clearColor];
    _textField.delegate = self;
   _textField.contentInset = UIEdgeInsetsMake(-4, -2, -4, 0);
   _textField.showsVerticalScrollIndicator = NO;
   _textField.showsHorizontalScrollIndicator = NO;
    _textField.font = [UIFont systemFontOfSize:15.0f];
    [_inputBackgroundView addSubview:_textField];
   [_textField release];

   [self adjustTextInputHeightForText:@""];

Fill UITextView delegate methods:

- (void) textViewDidBeginEditing:(UITextView*)textView {

   [self adjustTextInputHeightForText:_textField.text];
}

- (void) textViewDidEndEditing:(UITextView*)textView {

   [self adjustTextInputHeightForText:_textField.text];
}

- (BOOL) textView:(UITextView*)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString*)text {

   if ([text isEqualToString:@"\n"])
   {
      [self performSelector:@selector(inputComplete:) withObject:nil afterDelay:.1];
      return NO;
   }
   else if (text.length > 0)
   {
      [self adjustTextInputHeightForText:[NSString stringWithFormat:@"%@%@", _textField.text, text]];
   }
   return YES;
}

- (void) textViewDidChange:(UITextView*)textView {

   [self adjustTextInputHeightForText:_textField.text];
}

And the trick is...

- (void) adjustTextInputHeightForText:(NSString*)text {

   int h1 = [text sizeWithFont:_textField.font].height;
   int h2 = [text sizeWithFont:_textField.font constrainedToSize:CGSizeMake(_textField.frame.size.width - 16, 170.0f) lineBreakMode:UILineBreakModeWordWrap].height;

   [UIView animateWithDuration:.1f animations:^
   {
      if (h2 == h1)
      {
         _inputBackgroundView.frame = CGRectMake(0.0f, self.frame.size.height - _InputBarHeight, self.frame.size.width, _InputBarHeight);
      }
      else
      {
         CGSize size = CGSizeMake(_textField.frame.size.width, h2 + 24);
         _inputBackgroundView.frame = CGRectMake(0.0f, self.frame.size.height - size.height, self.frame.size.width, size.height);
      }
      CGRect r = _textField.frame;
      r.origin.y = 12;
      r.size.height = _inputBackgroundView.frame.size.height - 18;
      _textField.frame = r;

   } completion:^(BOOL finished)
   {
      //
   }];
}

You can use setFrame: or sizeToFit.

UPDATE:

I use sizeToFit with UILabel, and it works just fine, but UITextView is a subclass of UIScrollView, so I can understand why sizeToFit doesn't produce the desired result.

You can still calculate the text height and use setFrame, but you might want to take advantage of UITextView's scrollbars if the text is too long.

Here's how you get the text height:

#define MAX_HEIGHT 2000

NSString *foo = @"Lorem ipsum dolor sit amet.";
CGSize size = [foo sizeWithFont:[UIFont systemFontOfSize:14]
              constrainedToSize:CGSizeMake(100, MAX_HEIGHT)
                  lineBreakMode:UILineBreakModeWordWrap];

and then you can use this with your UITextView:

[textView setFont:[UIFont systemFontOfSize:14]];
[textView setFrame:CGRectMake(5, 30, 100, size.height + 10)];

or you can do the height calculation first and avoid the setFrame line:

UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(5, 30, 100, size.height + 10)];